WO2002004939A1

WO2002004939A1 - Method for sealing a porous shaped body and a retaining device for a shaped body of this type

Info

Publication number: WO2002004939A1
Application number: PCT/DE2001/002606
Authority: WO
Inventors: Robert Höhne
Original assignee: Hoehne Robert
Priority date: 2000-07-11
Filing date: 2001-07-10
Publication date: 2002-01-17
Also published as: DE10192656D2; AU2001283772A1; DE10033532A1; DE20121726U1

Abstract

The invention relates to a method for sealing a porous monolithic shaped body (1) in relation to a surface (2), to a retaining device for a porous monolithic shaped body and to a device for the chromatographic separation of at least two substances. According to said method, the surface, for example, a section of housing (2), is at least partially provided with a large number of extremely small projections (3). Said surface comprising projections is pressed against the porous monolithic shaped body (1), in such a way that the projections at least partially penetrate the shaped body. The areas which are immediately adjacent, on the external edge of the shaped body are thus sealed and the minutest particles of the porous structure break off and fall into the intermediate spaces between adjacent projections, where they accumulate and are swept with the passage of a liquid in the direction of flow against the projection lying downstream. This effect achieves a reliable seal between the porous structure and the casing.

Description

Method for sealing a porous shaped body and holder for such a shaped body

The present invention relates to a method for sealing a porous monolithic shaped body against a surface and a holder for a porous monolithic shaped body and a device for the chromatographic separation of at least two substances.

Monolithic moldings are used as sorbents, for example for the chromatographic separation of substances. A distinction is made here between a continuous and a discontinuous chromatographic separation. The first method and a device suitable therefor are described in DE 43 26 222 Cl and in DE 195 45 423 AI, the sorbent shaped body which is particularly suitable for this purpose being designed as a disk. The second method is disclosed in WO 98/58253, the sorbent shaped body which is particularly suitable for this purpose being designed as a column or cylinder.

Common to both processes is the use of sorbents in the form of porous monolithic substances, which are produced as molded articles for the respective intended use. Suitable substances and processes for the production of the shaped bodies are described in WO 98/59238 and in DE 196 27 924 AI. Ceramic or are particularly suitable for these moldings

Silica gel or polymer gel materials. Characteristic properties of these molded articles are the fine pore structure, which extends to the edge of the molded article, and the brittleness. At the same time, the task arises of accommodating the shaped body for receiving in the respective device and handling in a holder or casing, so that the shaped body is protected and the substances to be separated (the eluent) exclusively

> flow through the molded body. The sealing at the interface between the molded body and the respective holder or encasing is particularly problematic here, since here a liquid-tight, pressure-stable and against the

Substantially inert sealing must be achieved, but the porous materials do not have a sufficiently smooth outer surface, which would enable sealing with conventional seals and • the very fine pores can hardly be filled with common seals. A further problem, for example of silica gel materials, is their property of growing or shrinking again under the influence of moisture, which makes maintaining the sealing state even more difficult.

Against this background, a number of solutions have already been proposed, which are described in detail in conjunction with their inherent disadvantages in WO 98/59238. However, none of the previous solutions was able to achieve a really reliable seal with the required properties.

Proceeding from this, the object of the invention is to propose an alternative method for sealing a porous monolithic shaped body against a surface and a holder for a porous monolithic shaped body, which enables a reliable liquid-tight and pressure-stable seal.

According to a further aspect of the invention, ^" the

The choice of material enables a seal that is inert to the substances to be treated.

To achieve this object, the invention proposes a method according to claim 1 or 2, a holder according to claim 9 and a device for chromatographic separation according to claim 23. Preferred embodiments of the The method and the holder as well as the device are specified in the subclaims.

In essence, the invention is based on the knowledge that a large number of very small projections are provided for this at least in regions at the interface between a porous monolithic shaped body and the surface of a holder, and the surface is pressed with the projections against the porous monolithic shaped body, such that that the projections at least partially penetrate into the porous molded body.

The penetration of the protrusions of the surface into the molded body not only creates small barriers for the liquid with the substances to be separated in the edge area relevant for sealing technology, but also penetrates these areas by breaking the pores. In addition, very small fragments of the porous substance crumble away and get into the spaces between the adjacent protrusions, where they accumulate. If the liquid flows through the shaped body in this edge area, i.e. at the interface between the shaped body and the surface of the holder therefor, the loose smallest fragments are carried along in the gaps in the flow direction and accumulate on the projection adjacent in the flow direction, so that this results in an additional sealing effect is reached at this point.

When the method or the sealing structure is reversed, the projections described can also be molded onto the porous molded body and pressed against a surface against which the sealing is to be achieved in such a way that the projections break off at least partially because they are essentially not in can penetrate the surface. Here, too, the pores are compressed in the region of the projections of the molded body, and these edge regions are compressed accordingly. Moreover the broken off very small fragments reach the spaces between adjacent projections and cause the described sealing effect when flowing through the edge area.

Experiments have shown that this type of sealing is not only relatively inexpensive to produce, for example by machining, but is also clearly superior to all other previously tried solutions with regard to pressure resistance and sealing. By making the holder at least at the relevant contact points with the molded body and the substances to be separated from a material that is inert to these components, the requirement can be met without further ado that the sample results are not caused by washout, dissolving,

Reactions or the like. Unwanted influences can be influenced.

The invention is described in more detail below with reference to an exemplary embodiment shown in the accompanying drawing. Show it:

1 is an enlarged schematic representation of a hollow cylindrical holder and a cylindrical shaped body in section,

FIG. 2 shows a further enlarged schematic illustration of the detail A from FIG. 1,

3 shows a schematic illustration of a ^' plate-like holder for a disk-shaped molded body in plan view,

Fig. 4 is an enlarged schematic representation of a plate-like holder with a disc-shaped body in section and Fig. 5 is a schematic representation of a modification in which the projections are provided on the molded body.

FIG. 1 shows a holder for a porous, monolithic shaped body, as is used, for example, as a columnar sorbent for discontinuous separation processes.

The holder comprises a housing part 2 designed as a hollow cylinder body, into which a cylindrical porous monolithic molded body 1 is inserted. The inner cylinder surface facing the molded body 1 is provided with a multiplicity of very small projections 3, which are incorporated, for example, by a machining process, in particular by turning, by a cutting tool along the preferably uniform shaft contour, which can be clearly seen in FIG. 2, at least over one Part of the inner cylindrical surface of the hollow cylinder body is moved. Alternatively, a thread-like projection can be achieved by a high feed of the ^'cutting tool. The non-cutting production of the pre-sprays by molding or casting is also possible.

Although the wave contour is preferred, alternative shapes of the projections such as symmetrical or asymmetrical serrations, sawtooth shapes or trapezoidal projections are possible, provided that they can penetrate into the molded body.

As a result, the projections result in the form of knife-like concentric ridges or narrow edges 3, a depression 4 being formed in each case between adjacent ridges. The ridges of adjacent projections, depending on the overall size of the component, preferably have a distance D of 0.01 to 5 mm from one another and a height E of 0.01 to 0.5 mm, preferably 0.02 to 0.05 mm above the bottom of the depression between the ridges. The projections or ridges 3 are so dimensioned and to arrange that these, if they are pressed against the porous monolithic molded body during the connection between the housing part 2 and the molded body 1, can at least partially dig into the latter, as is schematically indicated in FIG. 2.

In the example of a hollow cylindrical housing part or casing, the pressure required for this can be achieved in such a way that the hollow cylinder body heats up after the burrs have been formed, and thus with a suitable choice of a starting material with sufficient

Coefficient of thermal expansion is achieved. If the porous molded body 1 with correspondingly adapted outer dimensions is then inserted in direction B into the inner cylinder part, the shrinkage of the hollow cylinder part produces when it cools down. the required all-round pressure in direction C on the molded body so that the burrs dig into it.

When penetrating, the pores of the surrounding areas on the outer surface of the molded body are slightly compressed and compressed. In addition, very small fragments of the porous substance break off and reach the spaces between the adjacent protrusions, where they accumulate. The liquid flows through the molded body in it

Edge area, i.e. at the interface between the molded body 1 and the surface of the housing part 2, the loose smallest fragments in the gaps are taken along in the direction of flow (indicated schematically in Fig. 2) and accumulate on the side of the gap in the direction of flow, so that an additional sealing effect is achieved at this point in that liquid cannot flow unhindered along the surface of the housing part between the molded body and the housing part. Although the projections are shown as concentric ridges that run essentially transversely to the direction of flow of a substance along the outside of the shaped body, the projections can also result from a spiral ridge with preferably a slight slope and thus run obliquely to the direction of flow.

Likewise, it may be sufficient not to provide the entire inner cylinder surface with burrs, but rather only a part or different, not necessarily contiguous areas thereof, which are required for sealing against the porous monolithic molded body.

Materials for the housing part that are inert with respect to the substances to be separated, such as steel in suitable alloys, e.g. Stainless steel, other metals and their alloys or plastics with the required properties such as Polyether ketones such as polyether ether ketones (PEEK) in unmodified or modified form, provided that they are sufficiently rigid and firm to be machined to form the burrs and to be able to withstand the pressures occurring during operation.

In a modification of the holder shown in FIGS. 3 and 4, which are used, for example, in devices for continuous chromatography, the housing part has two mutually parallel plates, on the mutually facing inner surfaces of which the surfaces provided with the projections are provided. As in the example described, the projections are designed here as concentric or as spiral ridges or narrow edges on the inner surfaces of the plates. A disc-shaped, porous, monolithic shaped body is inserted between the parallel plates, and the inner surfaces of the plates with the ridges facing the shaped body are covered Tensioning screws, which press the plates together, are pressed against the molded body until the projections dig into the molded body as described. This effect can be supported by the plates being rotated relative to the shaped body in the case of concentric burrs before or when the pressure is exerted. For the rest, in this variant, all modifications and aspects described in connection with the first embodiment are equally valid. •

In a likewise reversal of the mutually assigned and mutually sealed surfaces, which is indicated schematically in FIG. 5, the projections can be molded directly onto the porous molded body, while the surface of the housing part serving as the casing does not have to have the projections, but of course in combination that can have effects.

In this variant, a large number of very small projections are provided on an outer surface of a porous monolithic molded body, at least in some areas. This outer surface of the molded body with the projections is assigned the housing part with a surface such that the outer surface of the molded body with the projections is pressed against the surface in such a way that the projections break off at least partially on the harder surface because they essentially do not penetrate into the Surface can penetrate. Here, too, the pores are compressed in the region of the projections of the molded body and these edge regions are compressed accordingly. In addition, the broken-off, very small fragments reach the interspaces between adjacent projections and, when flowing through the edge area, bring about the sealing effect already described with reference to the other exemplary embodiments.

Both the type of materials of the surface pairing and the type and shape of the projections can correspond to those of the previously described exemplary embodiments, the most preferred variant of the production is a direct molding of the projections when producing the shaped body. However, machining or shaping production is also conceivable here.

The unit made of porous molded body and housing part, which are sealed against each other, which can be produced according to all variants, can be integrated as a unit into other devices and housings without any problems, since a seal between the housing part on the one hand and further housing parts or

Components is unproblematic and can be done according to known methods (gluing, welding, screwing with seals, etc.).

As already described at the beginning, the porous monolithic shaped body to be accommodated or accommodated in the holder according to the invention consists of silica or polymer gel, the unit formed in this way being particularly suitable as or in devices for chromatographic separation of at least two substances, which were also described at the outset ,

Claims

claims

1. A method for sealing a porous monolithic shaped body against a surface, the surface being provided at least in regions with a large number of very small projections and the surface with the projections being pressed against the porous monolithic shaped body in such a way that the, projections are at least partially in penetrate the porous molded body.

2. Method of sealing a porous monolithic

Shaped body opposite a surface, the monolithic shaped body on an outer surface at least in regions with a large number of very small

Is provided with projections and the outer surface of the molded body is pressed with the projections against the surface such that the

At least partially break off the projections.

3. The method of claim 1 or 2, wherein the projections obliquely or preferably substantially transverse to one

Flow direction of a substance can be arranged along the outside of the molded body.

4. The method of claim 1, 2 or 3, wherein the protrusions are a blade-like ridge or a narrow one

Have edge and a recess is formed between adjacent ridges or edges.

5. The method according to claim 4, wherein the ridges or edges of adjacent projections a distance of 0.05 to 5 mm from each other and a height of 0.01 to 0.5, preferably of 0.02 to 0.05 mm above the bottom of the recess in between.

6. The method according to any one of claims 1 to 5, wherein the surface and the molded body by acting from the outside

Clamping forces or by contraction due to cooling after thermal expansion are pressed against each other.

7. The method according to any one of claims 1 to 6, wherein the surface consists of a substantially rigid material and the projections are formed in the surface by a cutting or a shaping, non-cutting process.

8. The method according to any one of claims 1 to 6, wherein the surface consists of a substantially rigid material and the projections are molded onto the porous molded body during the production thereof.

9. Holder for a porous monolithic molded body, with a housing part that has a surface that for

Sealing with respect to the porous monolithic shaped body is provided at least in some areas with a large number of very small projections and the projections are dimensioned and arranged such that when they are pressed against the porous monolithic shaped body they can at least partially penetrate into it.

10. Holder according to claim 9, wherein the projections are arranged obliquely or preferably substantially transversely to a direction of flow of a substance along the outside of the molded body, against which the surface is to be sealed.

11. Holder according to claim 9 or 10, wherein the projections have a blade-like ridge or a narrow edge and a recess is formed between adjacent ridges or edges.

12. Holder according to claim 11, wherein the ridges or edges of adjacent projections a distance 0.05 to 5 mm from each other and a height of 0.01 to 0.5, preferably from 0.02 to 0.05 mm above the bottom of the have intermediate recess.

13. Holder according to one of claims 9 to 12, wherein the housing part consists at least in the region with the surface provided with the projections of an essentially rigid material, preferably of metal or metal alloys or plastics, preferably of stainless steel or PEEK.

14. Holder according to one of claims 9 to 13, wherein the housing part is assigned a porous monolithic shaped body such that the surface with the projections is pressed against the shaped body such that the projections have at least partially penetrated into the shaped body.

15. Holder according to one of claims 9 to 14 ^" , wherein the housing part comprises a hollow cylinder body and the surface provided with the projections is at least part of the inner cylindrical surface of the hollow cylinder body.

16. Holder according to claim 15, wherein the projections are or are formed as concentric ridges or narrow edges or as a spiral ridge or edge on the inner cylindrical surface of the hollow cylinder body.

17. Holder according to one of claims 9 to 14, wherein the housing part has two mutually parallel plates and the surface provided with the projections is provided on the mutually facing inner surfaces of the plates.

18. Holder according to claim 17, wherein the projections are designed as concentric or as spiral ridges or narrow edges on the inner surfaces of the plates.

19. Holder according to claim 15 or 16, wherein in the

Hollow cylinder body is a cylindrical porous monolithic molded body is used and the inner cylinder surface facing the molded body with the projections is pressed against the molded body such that the projections have at least partially penetrated into the molded body.

20. Holder according to claim 17 or 18, wherein a disc-shaped porous monolithic shaped body is inserted between the parallel plates and the inner surfaces of the plates facing the shaped body with the

Projections are pressed against the molded body in such a way that the projections have at least partially penetrated the molded body.

21. Holder according to one of claims 9 to 20, wherein the porous monolithic molded body consists of silica or polymer gel.

22. Use of a holder according to claim 14, 19 or 20 for the chromatographic separation of at least two

Substances.

23. Device for the chromatographic separation of at least two substances, with a porous monolithic shaped body, αer on one

Outer surface is at least partially provided with a large number of very small projections and a housing part with a surface that the

Shaped body is assigned so that the outer surface of the shaped body with the projections is pressed against the surface such that the projections at least partially break off and the molded body is thereby sealed off from the surface.

24. The apparatus of claim 23, wherein the projections obliquely or preferably substantially transverse to one

Flow direction of a substance along the outside of the molded body, against which the surface is sealed, are arranged.

25. The apparatus of claim 23 or 24, wherein the

Protrusions a blade-like ridge or a narrow one

Have edge and a recess is formed between adjacent ridges or edges.

26. The apparatus of claim 25, wherein the ridges or

Edges of adjacent projections have a distance of 0.05 to 5 mm from one another and a height of 0.01 to 0.5, preferably 0.02 to 0.05 mm above the bottom of the recess in between.

27. The device according to any one of claims 23 to ^'26, wherein the housing part at least in the region which is associated with the molding of the outer surface provided with the protrusions made of a substantially rigid material, preferably of metal or metal alloys or plastic materials, preferably of stainless steel or PEEK.

28. Device according to one of claims 23 to 27, wherein the projections are or are designed as concentric ridges or narrow edges or as a spiral ridge or edge on the outer surface of the shaped body.

29. The device according to any one of claims 23 to 28, wherein the porous monolithic shaped body consists of silica or polymer gel.